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HENRY DRE'YF'US, 0F BASEL, SWITZERLAND.

MANUFACTURE OF ACETIG ACID FROM ,AGETALDEHIYDE.

No Drawing. I

To all whom it may concern:

Be it known that l, HENRY Dnnrrus, of Basel, Switzerland, have inventedcertain new and useful Improvements in the Manufacture of Acetic Acidfrom Acetaldehyde, of whichthe following is a specification.

Various processes have been proposed for manufacturingacetic acid byoxidation of acetaldehyde with oxygen or air.

v'lhe present invention has reference to an improved. process for thispurpose.

According tomy present invention, liquid acetaldehyde is'oxidized toform acetic acid by introducing oxygen, air or other gas containing freeoxygen at substantially atmospheric pressure, into the liquidacetaldehyde maintained at a temperature of between about 0 6., andabout 10 (1.,while thoroughly agitating the liquidacetald'ehyde forinsuring thorough subdivision and intimate contact between the enteringgas and the liquid acetaldehyde, the reaction being carried out eitherwithout contact substances, or in the presence of ferric oxid, ferricacetate, or mixtures of ferric oxid and ferric acetate as contactsubstances.

If the temperature is reduced below 0v (3., the formation andaccumulation of 'peracid takes place which is very dangenous by:

reason of the liability "of. explosion, owing to spontaneous rise oftemperature occurring, which cannot becont-rolled.

Asbefore mentioned, the reaction of the present invention can beeifected very satisfactorily without any contact materials. I may,however, employ ferric oxid, or ferric I acetate, or mixtures of. both,as contact material, to increase the speed and intensity of thereaction.

By means of the presentinvention it is 1 possible to produce acetic acidin a simple theoretical-so that only about the theoretical quantity ofoxygen needs to be introduced.

andpflicient manner witha very high yieldrelatively. to the acetaldehydeemployed. With good working the conversion of "acetaldehyde into aceticacid can be practically ln carrying out the invention with oxygen forexample, this may be led into the liquid acetaldehyde (pure andundiluted) in a reaction vessel or chamber while maintaining theacetaldehyde at a. temperature between 0 and 10 0., and keeping theacetaldehyde in strong agitatiomfor example by a rotary agitatorrevolving at a highspcod, each as.

Specification of Letters Patent.

this is given Patented July 1, 1919.

Application filed J anuary'19, 1918. Serial No. 212,594.

5(l0 to 1000"revolutions or more per minute, Q

so as to subdivide or atomize the entering gas in contact with theliquid. A condenser should be provided at the outlet from the 'oxygen'inthe operation can be seen by connecting to'the gas outlet from thecondenser a plpe depending into liquid so as to form a liquid columngage. On reducing .the

v speed of the agitator, it will be seen from the descent of the liquidcolumn in the pipe, and

escape of oxygen, that the oxygen is absorbed less and less, inproportion to the decrease of speed, until there is practically noabsorption, and at last at a certain point, although there may be a fairagitation of the liquid acetaldehyde, practically none of the oxygenpassed in will combine with the acetaldehyde. It is, therefore,essential to maintain a very strong agitation to insure that the liquidacetaldehyde shall be brought into thorough andintimate contact with theoxygen. 3

Instead of oxygen, air may be employed, but in this case care must betaken to employ a-more powerful condensing apparatus at the outlet from.the reaction apparatus, to

cause the aldehyde partially entrained by the air to fall back into thereaction apparatus. With this precaution it will be found that beyondthe condensinglapparatus only nitrogen issues, with or wit out traces bytesting or analysis-cit the issuing gas.

The temperature to be maintained r for the reaction is between about 0and 10 C; 'As

considerable heat is liberated in the reaction it is necessary to coolin a suitable way, for

of oxygen and acetaldehyidaas can be shown example with water or salinesolutions, to

- maintain this low temperature.

. The manner in which the invention may be carried into effect isillustrated by the following example, it being understood that by way ofillustration only and is in no way restrictive.

Example 1: Into 20 kilograms of aicetaldehyde contained in an apparatus,preferably agitating, cubic meters of oxygen. The

, a{Cid med s is ll o f -1 of cylindrical form, provided-with an- I tor,capable of a speed of about 1000 revolu tions per minute and ofcompletely atomizing the bubbles of gas introduced, WhlGllrBPr' paratusis fitted with a reflux condenser for the aldehyde, there areintroduced, while a orption takes a e in a 15 to 25 hours. (gale istakenby keep the tem erature always tween fut 0- 1 1.. ,the'c y is. troduoedthe liquid Qclsjand orins acetic acid of 100% H ns ead of xy e ne-tan mpy r u in t i case are. mua aken, s b

period ofiabout t o t flux condenser, orderto retain all the ald ydeAfterward he eck leadi t the reflux condenser is closed and a cock eadito a descending condenser is oprened and the he y e d var e b en Wa d lThe reactionv can be accelerated by the employment of ferric oxid (Fe Oor ferric acetate (normal or basicMQr mixtures thereof,

The procedure when'employing said con= tact agents, mayibe explained bythe followg p hich. i g n so ely by ay f illustration; v

Example 2: 1 kilogramof ferric oxid and 1 kilogram of ferric acetate(normal or basic) are mixed with 20 kilograms of acetaldehyde and thesame quantity of oxygen or air in xample 1 isintroduced, observing thesame conditions of working, as in Exam Is 1.

he yield is ap roximately theoretical and the reaction is ours. Theferric-acetate may be omitted and the ferric oxid may be employed alone,or conversely.

- I If the rocess is performed in accordance.

with the indications above-given, and in particular in accordance withthe examples described, the danger of explosion, due either to theformation of peraci'ds, or other causes,

ished about 10 to 15 and intimate contact thereof with the liquidacetaldehyde by strong agitation, substantially as described.

2. A process of making acetic acid from acetaldehyde, which comprisespassih a gas containing free oxygen at substantia ly atmosphericpressure through liquid acetaldehyde in the presence of ferric oxid as acatan -l yzer, while maintaining the liquid at a temfore mentioned, tohaveja more powerful reerature between about 0 0., and about 10 a in stng agi Sub an ia y as d ed,

3. A process of making acetic acid from acetaldehyde, which comprisespassing a gas cnntaininfree oxygen at about atmo heric pressure roughliquid acetaldehyde, 1n the presence of ferric oxid and ferric acetateas catalyzers, while maintaining the liquid at a tem .eratu're betweenabout 0 0., and about 10 0,, and subjecting the liquid and entering gasto powerful agitation to maintain a thorough mixture, substantially asdescribed.

4.,A process of making aceticacid from acetaldehyde, which comprisespassing air at substantially atmospheric pressure through liquidacetaldehyde maintained at a temperature between about 0 0. and about 100., while insuring thorough subdivision of the entering air and intimatecontact thereof with the liquid acetaldehyde, by powerful agitation,substantially as described.

5. A process of making acetic acid from acetaldehyde, which comprisesintroducing air into liquid acetaldehyde containing a ferric compoundadapted to act as an oxygentransferring catalyst, subdividing theair sointroduced into the form of minute particles distributed through thebody of liquid, by

powerful agitation, naintaimng the temperature of the liquid between theapproximate limits of 0 0., and 10 0., substantially as described.

HENRY nnnY Us;

